Eliminating Bradenhead Pressure in the DJ Basin April 2019
Well Abandonment with Wel-lok™ CRT
A client in the Colorado DJ Basin was abandoning a well with Bradenhead pressure on the surface casing. After multiple attempts to address this pressure with conventional methods, they called BiSN to utilize the V0 Wel-lok™ technology.
1: Issues to overcome
Not wanting to mobilize a rig for this operation, this well was to be abandoned with wireline only. This meant, unlike previous deployments to address Bradenhead pressure, a section milled window would not be cut in the production casing. Instead, the casing was perforated multiple times to not only create holes for the liquid bismuth alloy to flow but also break the cement behind the casing to allow the alloy to intersect the channels in the cement.
Multiple perforation guns were deployed over the same interval to break up the cement behind the 4 ½” production casing followed by setting of a Wel-lok™ CRT across the perforated interval. The bismuth alloy was melted and allowed to flow through the perforations to create a solid plug out to the open hole.
The CRT plug was successfully pressure tested to 500 psi. A 16-hour inflow test and further gas sampling concluded that the source of the gas causing the Bradenhead pressure was above the setting depth of the CRT.